Summary: This lesson will focus on other forms of heritance aside from Mendelian genetics, such as incomplete dominance, codominance, multiple alleles, and polygenic traits. We will also touch upon how an organism's environment can affect its genetic makeup. Most of this lesson will be spent investigating blood types and solving a mystery activity.
Objectives: Students will explain the concepts of incomplete dominance, codominance, and polygenic traits. Students will explain the definition of a multiple allele trait and give an example. Students will create Punnett Squares to show the crosses of multple allele traits. Students will show the relationship between terms and processes disucssed so far in this unit by creating a concept map.
Instruction: Opening: As students walk into the room, I will tell them to look at the diagram on the board and answer the question that's written. There will be a Punnett square drawn on the board that shows a cross between a white and red flower. It will look like this:
R
R
W
RW
RW
W
RW
RW
(Flowers will be drawn on the top and side of the Punnett square to show students that the trait is on a flower)
The question will be: What do you predict is going on in this Punnett square? What's being crossed and what is the result?
I will give students about 5 minutes to write down their predictions and then start a discussion.
"So far in this unit we have discussed all of Mendel's experiments and results. Mendel got us started with his theories in the 1800s, but scientists that came along later discovered that there are many other ways we can inherit genes that don't necessarily follow Mendel's principle of dominance." Middle:
I will ask for students' ideas about the Punnett square on the board and then explain that this is an example of incomplete dominance. Codominance, multiple alleles, and polygenic traits will also be brielfy explained and students will write all of the definitions in their notes. I will also introduce the debate about Nature vs. Nurture and how phenotypes are only determined partially by the genotype. In other words, a person's environment plays a role in the expression of their genes. The opening discussion and explanation should use about 25 minutes of class time.
The rest of the period will be spent talking about blood types and then doing a mystery activity. In order to connect the material to students' lives, I will first start a discussion about their own blood types. "Does anyone know what blood type they are? What other blood types are there? What determines your blood type?"
I will then give notes that describe the three alleles for blood types and describe the inheritance pattern (A and B are codominant to each other and are both dominant over O). I will model a few crosses between parents with different blood types and then students will work with partners to solve the "Blood Type Mystery." This activity requires students to act as lawyers in a case that involves a "long lost son" of a famous man who is trying to inherit part of the man's millions. Students will determine if this person is actually the man's son by using the blood types of all the people involved.
Closing: Since the worksheet only has one problem, students should have time after they finish to create a concept map with all the terms and processes we've learned so far in this unit. The concept map should be labeled with connecting words so that I can see that students understand the relationships among the terms. As students finish up their maps, I will have them share it with the class and guide them to any corrections they should make.
Homework: Study for quiz! Finish the concept map if you haven't already.
Assessments: 1. Formative assessment- the dihybrid cross activity will be collected and counted as a lab grade. I will see that students now know how to create Punnett squares for crosses and test their predictions.
2. Formative assessment- by looking at students' concept maps, I can pinpoint any confusions that students still have about the material before they take their quiz next class.
Summary:
This lesson will focus on other forms of heritance aside from Mendelian genetics, such as incomplete dominance, codominance, multiple alleles, and polygenic traits. We will also touch upon how an organism's environment can affect its genetic makeup. Most of this lesson will be spent investigating blood types and solving a mystery activity.
Objectives:
Students will explain the concepts of incomplete dominance, codominance, and polygenic traits.
Students will explain the definition of a multiple allele trait and give an example.
Students will create Punnett Squares to show the crosses of multple allele traits.
Students will show the relationship between terms and processes disucssed so far in this unit by creating a concept map.
Materials:
Blood Type Mystery worksheet
Instruction:
Opening:
As students walk into the room, I will tell them to look at the diagram on the board and answer the question that's written. There will be a Punnett square drawn on the board that shows a cross between a white and red flower. It will look like this:
The question will be: What do you predict is going on in this Punnett square? What's being crossed and what is the result?
I will give students about 5 minutes to write down their predictions and then start a discussion.
"So far in this unit we have discussed all of Mendel's experiments and results. Mendel got us started with his theories in the 1800s, but scientists that came along later discovered that there are many other ways we can inherit genes that don't necessarily follow Mendel's principle of dominance."
Middle:
I will ask for students' ideas about the Punnett square on the board and then explain that this is an example of incomplete dominance. Codominance, multiple alleles, and polygenic traits will also be brielfy explained and students will write all of the definitions in their notes. I will also introduce the debate about Nature vs. Nurture and how phenotypes are only determined partially by the genotype. In other words, a person's environment plays a role in the expression of their genes. The opening discussion and explanation should use about 25 minutes of class time.
The rest of the period will be spent talking about blood types and then doing a mystery activity. In order to connect the material to students' lives, I will first start a discussion about their own blood types.
"Does anyone know what blood type they are? What other blood types are there? What determines your blood type?"
I will then give notes that describe the three alleles for blood types and describe the inheritance pattern (A and B are codominant to each other and are both dominant over O). I will model a few crosses between parents with different blood types and then students will work with partners to solve the "Blood Type Mystery." This activity requires students to act as lawyers in a case that involves a "long lost son" of a famous man who is trying to inherit part of the man's millions. Students will determine if this person is actually the man's son by using the blood types of all the people involved.
Closing:
Since the worksheet only has one problem, students should have time after they finish to create a concept map with all the terms and processes we've learned so far in this unit. The concept map should be labeled with connecting words so that I can see that students understand the relationships among the terms. As students finish up their maps, I will have them share it with the class and guide them to any corrections they should make.
Homework: Study for quiz! Finish the concept map if you haven't already.
Assessments:
1. Formative assessment- the dihybrid cross activity will be collected and counted as a lab grade. I will see that students now know how to create Punnett squares for crosses and test their predictions.
2. Formative assessment- by looking at students' concept maps, I can pinpoint any confusions that students still have about the material before they take their quiz next class.